The AK-47, or Kalashnikov rifle, is one of the most common firearms globally. Its simple and reliable design makes it economical to manufacture and easy to maintain in the field. While the AK-47 is a versatile weapon, it does lack some features that would improve its usefulness in combat.
One of the most problematic gaps in the AK-47's design is the lack of an automatic bolt hold-open. When the last cartridge in the firearm's magazine is spent, the bolt returns to the closed position without picking up a cartridge. After replacing the empty magazine with a full magazine, it is necessary to manually pull back the bolt to chamber the first cartridge of the new magazine. Although this action only requires a few seconds, it is distracting and annoying, or worse in the case where every second counts. Additionally, when at a shooting range, range officers may at times require the bolt to be held in the open position for safety so a bolt hold-open would be beneficial.
A mechanism that would automatically hold the bolt open when the last round was ejected from the magazine, while allowing the bolt to be easily released when a new magazine is in place, would remove the necessity of manually chambering the new round, would satisfy shooting range regulations, and would provide a significant advantage in speed and convenience of changing magazines. Such a device would also minimize mental distraction, allowing the firearm user to direct more of his or her attention to the surroundings.
U.S. Pat. No. 7,261,029 issued to Davis provides a bolt hold-open for an AK-47, but the system disclosed by Davis requires the modification of the bolt carrier, the receiver carrier, and the magazine. A system that limits modifications to the gun is preferable, since it allows the use of a wider variety of replacement parts. Furthermore, the bolt hold-open release mechanism of the system provided in Davis cannot be activated by the trigger hand since the mechanism is high on the gun, and the Davis bolt hold-open can only be released on one side of the gun. A system which allowed the locking mechanism to be released by the trigger hand would be preferable, as would a system that could be easily operated either left- or right-handed.
Other available retrofit bolt hold-open devices do not hold the bolt fully open.
Accordingly, there is a need for a bold hold-open system that holds the bolt within the bolt carrier fully open, can be operated with either hand, can be accessed with the trigger hand, and requires no more than minimal modification to the gun.